THERMALLY CURABLE 2ND-ORDER NONLINEAR-OPTICAL POLYMER

A thermally cross-linkable, second-order nonlinear optical (NLO) polymer containing ethynyl groups has been synthesized. The ethynyl groups in the polymer backbone can undergo thermal intramolecular or intermolecular reactions with amide groups to form heterocyclic structures or cross linkages. The thermal curing of the polymer can be simultaneously effected during electric poling and second-harmonic generation measurements indicated that the cured polymers indeed showed high stability in dipole orientation; no obvious decay at room temperature for more than 1000 h. Long-term stability of second-harmonic coefficients was observed even at 90-degrees-C, at least for 500 h.